Copenhagen police Tuesday cordoned off an area around the site of a deadly weekend attack after discovering a "suspicious" letter but later said no explosives had been found

Copenhagen police Tuesday cordoned off an area around the site of a deadly weekend attack after discovering a "suspicious" letter but later said no explosives had been found.
  
"Investigation finished. No explosives. Cordon has been lifted," police wrote on Twitter. Police are on high alert after the weekend attacks on a cultural center and a synagogue that left two people dead.
  
Police also arrested a man in Mjoelerparken, the same area where suspected gunman Omar El-Hussein was from, but declined to comment on media reports that it was linked to the attacks.
  
Two men were charged on Monday with helping the suspected gunman, who was killed in a shootout with police on Sunday, and detained in custody for 10 days. "It's a very big investigation, very tough. There's a lot of surveillance material and Internet data to go through. It's a huge and complicated investigation," police spokesman Steen Hansen told AFP.